A pond had 60 fish, out of which, all but 20 died.
How many fishes are now present in that pond?

A boy purchased a book from a bookkeeper and gave him $100.
The cost of the book is $50 but the bookkeeper has no change, so he gets the change from the next shop and returns the boy his $50.

After some time the next shopkeeper came with the $100 note and told the bookkeeper that the note was a fraud, so he took the money back.

How much loss did the bookkeeper face?

Jigsaw captured 100 people and make them stand in a circle and all these people are labelled as Person1, Person2, Person3... Person100. He made them play a crazy game in which Person 1 shot Person 2 and pass the gun to the next person and so on until one stands alive.

Which person will survive in the end?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Can you convert the number zero(0) into a positive number using just one mathematical operator ?

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

There are three boxes of different sizes with three cupcakes inside each of the boxes in Christina's kitchen. At night her daughter wakes up and goes to the kitchen. She opens a box and eats all three cakes.

But in the morning Christina finds out that each box still had three cupcakes. How?

Take 9 from 6, 10 from 9, 50 from 40, and leave 6.

How Come ??

A bomb goes off.
Carnage.
One person, only a few feet away, survives! How can this be?